The invention concerns a hydrodynamic machine, especially a hydrodynamic retarder, which, in known fashion, has a rotor and a stator, both of which together form a hydrodynamic working chamber. Various liquids are considered as medium, for example, oil or water. The areas of use are in both stationary and mobile fields. DE 196 23 680 A1 can be referred to merely as an example from the variety of publications.
During operation of a retarder with specific bearing arrangements, out-of-true running of the rotating parts can occur and therefore contact of such parts on other components. For example, striking of the rotor on the stator can occur, as well as asymmetric wear of seals. In unfavorable cases, this can lead to failure of the entire retarder.
The underlying task of the invention is to configure a retarder so that out-of-true running and striking of rotating parts is reduced or avoided.
The inventors recognized the following:
If the retarder is hot during operation, this leads to nonuniform expansion of individual components, since these consist of different materials. The essentially cup-shaped retarder housing generally consists of aluminum. It expands more strongly than other components produced from other materials. This is particularly true of the rotor housing, which consists of ferritic material.
Radial play therefore occurs between the retarder housing and the rotor housing. The length changes that develop remain uninfluenced, and the axial forces of the hydrodynamic circuit are taken up by the support ring.
The solution according to the invention consists of providing a balancing element, consisting of a material that has at least roughly the same heat expansion coefficient as the retarder housing.
This has the following effect: If the retarder housing expands, owing to heat development of the retarder, to a certain degree, the balancing element undergoes similar expansion. Warping of the rotor housing over the balancing element therefore occurs with the retarder housing, i.e., centering of the bearing is retained.
Generally, the mentioned balancing element is designed as a ring. If the retarder housing consists of aluminum, as is generally the case, aluminum is also chosen as material for the balancing ring.